Heart palpitations are moments when you become unusually aware of your own heartbeat. They can feel like your heart is pounding, fluttering, racing, or skipping a beat. They’re extremely common, accounting for roughly 16% of all complaints in general practice, and the vast majority are harmless. That said, certain patterns deserve attention.
Why You Can Suddenly “Feel” Your Heart
Your heart sends beat-by-beat sensory information to your brain through nerve pathways, including the vagus nerve. Normally, your brain filters this information out, the same way you stop noticing the feeling of clothes on your skin. A palpitation happens when something disrupts that filtering, either because the heartbeat itself changes or because your brain becomes more tuned in to signals from the body.
This process, called interoception, routes through brain areas involved in both body awareness and emotion. That’s why anxiety and palpitations are so tightly linked: the emotional centers and the heart-sensing centers overlap. It also explains why palpitations often feel disproportionately alarming. Your brain is wired to pay attention once it notices something unusual in the chest.
What They Actually Feel Like
People describe palpitations in several distinct ways, and the sensation often hints at what’s happening electrically in the heart.
- A skipped beat or “thud”: Usually caused by premature beats, which are extra heartbeats that fire slightly early. The heart then pauses briefly before the next regular beat, and that pause (plus the stronger beat that follows it) is what you notice. These can originate in the upper chambers (premature atrial contractions) or the lower chambers (premature ventricular contractions). Almost everyone has them occasionally.
- A fluttering or quivering sensation: Often associated with atrial fibrillation or other irregular rhythms where the upper chambers of the heart fire chaotically instead of in a steady pattern.
- A sudden racing that starts and stops abruptly: Characteristic of supraventricular tachycardia, a type of fast rhythm originating above the lower chambers. The heart rate can jump to 150 or more beats per minute and then snap back to normal just as quickly.
- A pounding heartbeat: Common during exercise, after caffeine, or during moments of strong emotion. The heart is beating harder or faster than usual, but the rhythm itself may be perfectly normal.
Common Triggers
Most palpitations trace back to everyday triggers rather than heart disease. Caffeine, nicotine, and alcohol are among the most frequent culprits. Cold and cough medications containing pseudoephedrine can also set them off, as can stimulants like amphetamines and cocaine.
Stress and strong emotions are powerful triggers. Job interviews, public speaking, bad news, even making a phone call can activate your body’s fight-or-flight response, flooding the heart with adrenaline and making you hyper-aware of every beat. Depression and chronic anxiety can keep this cycle running in the background for weeks.
Hormonal shifts during menstruation, pregnancy, and menopause frequently cause palpitations. Fever, strenuous exercise, and dehydration are physical triggers that raise heart rate and make beats more noticeable. Even a large meal can do it, since blood flow shifts toward the digestive system and the heart compensates by working a bit harder.
Medical Conditions That Cause Palpitations
When palpitations are persistent or don’t line up with obvious triggers, an underlying condition may be involved. An overactive thyroid gland speeds up metabolism across the entire body, including heart rate, and palpitations are one of its hallmark symptoms. An underactive thyroid can cause them too, though less commonly. Anemia, where the blood carries fewer oxygen-rich red blood cells, forces the heart to pump faster to compensate, producing that racing or pounding sensation.
Electrolyte imbalances, particularly low potassium or magnesium, can make the heart’s electrical system misfire. These imbalances sometimes develop from dehydration, intense exercise, or certain medications like diuretics. Heart valve problems and other structural heart conditions can also present as palpitations, though this is less common in people without a known cardiac history.
How Palpitations Are Evaluated
The first step is usually a conversation about your medical history, your symptoms, and your lifestyle, including caffeine, alcohol, and medication use. If your provider suspects an irregular rhythm, several tools can capture what your heart is doing electrically.
An electrocardiogram (ECG) records your heart’s electrical activity through sticky patches placed on your chest. It takes seconds and is painless, but it only captures a snapshot. If your palpitations come and go, a normal ECG doesn’t rule everything out.
For intermittent symptoms, a Holter monitor is a portable ECG you wear for 24 hours or more while going about your day. It records continuously, catching irregular rhythms that a brief office ECG might miss. If episodes are even less frequent, an event recorder works differently: you wear it for up to 30 days and press a button when you feel symptoms, so the device captures the heart’s rhythm at that exact moment. Some smartwatches now offer basic ECG monitoring as well, which can provide useful data between visits.
What You Can Do During an Episode
For certain fast rhythms, particularly supraventricular tachycardia, vagal maneuvers can sometimes reset the heart’s rhythm on the spot. These techniques stimulate the vagus nerve, which slows electrical conduction through the heart.
The most practical one to try at home is the Valsalva maneuver: take a deep breath and bear down as if you’re straining, or blow hard into a syringe or closed fist for 10 to 15 seconds. A modified version, where you do this while sitting upright and then immediately lie flat with your legs raised, has shown conversion rates above 40%, roughly double the success rate of the standard technique.
The diving reflex is another option. Sit comfortably, take several deep breaths, hold one in, and submerge your face in a basin of cold water. The cold triggers a reflex that slows the heart. These techniques work best for specific types of fast rhythms and won’t do much for isolated skipped beats, but they’re safe to try and can spare you a trip to the emergency room.
Beyond acute episodes, reducing caffeine, managing stress, staying hydrated, getting adequate sleep, and avoiding known triggers can significantly reduce how often palpitations occur.
Signs That Need Prompt Attention
Most palpitations are benign, but certain combinations of symptoms raise the stakes. Palpitations accompanied by fainting or near-fainting (especially if a fall causes injury), chest pain, or significant shortness of breath warrant urgent evaluation. A resting heart rate above 120 beats per minute or below 45, a new irregular rhythm you haven’t experienced before, a personal history of heart disease, or a family history of sudden cardiac death are all considered red flags that increase the likelihood of a serious underlying rhythm disorder.